The present invention relates to a method of and a device for detecting oil pollutions on water surfaces.
A method of detection of oil film on water surface is known from inventor's certificate of the USSR # 1,354,073. In the method the investigated water surface is illuminated by pulsed optical beam and the reflected signal is received. Comparison of signals from clean and from investigated water areas is conducted. Amount of pulses, which exceeds the threshold of the analyser, is selected as comparison parameter. If N≧Nb then it is supposed that oil film is present, and if N<Nb then oil film is not present. Nb is a quantity that specifies probability of signal reception in roughness conditions. A disadvantage of this method is low reliability of detection.
Another method of oil pollution detection is disclosed in patent Russian Federation No. 2,143,108. Water surface is irradiated by pulsed optical beam and the reflected signal is received. Comparison of signals from clean and from investigated water areas is conducted. Energy of echo pulses are selected as comparison parameters. It is supposed that oil film is present if both conditions are fulfilled:W>W0τ<τ0where W1 W0 and τ<τ0 are energies and widths of echo pulses reflected from investigated and clean water areas correspondingly. A disadvantage of this method is false detection of oil pollution in the presence of areas with smoothed wind roughness on clean water surface.